“CSI technique leads Italian police to bloody footprint in Foxy Knoxy’s bedroom,” Britain’s sleazy Daily Mail once claimed. Until recently, even Wikipedia insisted that police had found bloody, luminol-revealed footprints in the “house of horrors.” Prosecutors claimed the prints were “compatible” with the feet of U.S. college student Amanda Knox and Raffaele Sollecito, the ex-lovers convicted of the murder of Meredith Kercher. Their alleged co-conspirator, petty burglar Rudy Guede, left bloody shoeprints from the victim’s bedroom to the front door.

Yet investigators had tested the luminol footprints for blood and found them lacking, a truth carefully hidden from December 17, 2007 (when they were collected) until September 2009, when defense expert Sarah Gino outed the negative test during the trial that led to Knox and Sollecito’s conviction. Even now “bloody footprints” are the Knox case’s most persistent urban legend.

“Luminol identified nine prints in the cottage, but none were derived from blood,” notes Oggi investigative reporter Maria D’Alia in The Crime of Perugia: The Other Truth, a refreshingly fact-based book on the Knox case.

“Tetramethylbenzidine, the test that reveals blood, gave negative results,” she continues. “Also, in this case, the court has affirmed that this outcome arrived from the prints in question. Tetramethylbenzidine(TMB) is considered a sensitive and reliable test that excludes the presence of blood.”

So how did a falsehood that prejudicial fly around the world?

“I cannot tell how the truth may be; I say thetale as it was said to me,” said Sir Walter Scott.

Timeline: Luminol-Revealed Footprints, House of Horrors

Luminol footprint said to be compatible to Amanda Knox's foot. Her roommates' feet were never measured. Perugia Shock

*December 17, 2007. Police learn that a bloody Nike shoeprint found by the victim’s bed is the wrong size and style to pin on Raffaele Sollecito–and belongs instead to Rudy Guede (a fact they’ll conceal until May 15, 2008, when Rudy finally admits it). Nothing else connects Raffaele to the crime. Forensics investigators swoop down on the “house of horrors,” more than one month after Kercher’s slashing. They make a show of finding a now-rusted, untestable bra clasp. The tiny metal clasp has levitated across the room and ended up under a dirty carpet. They handle it with stained gloves and drop it on the trampled floor to be photographed–and only then send it off to Rome for testing.

“All of a sudden, someone remembered the hook,” writes Giangavino Sulas of Oggi. “They rushed to recover it in a house that had, in the meantime, undergone three searches. They found it and, surprise, there was the DNA of Raffaele.”

But they didn’t stop there. Before this search, they’d also visited Amanda, Raffaele and alleged co-conspirator Rudy Guede in their jail cells. With great fanfare, they’d taken their footprints. Now they apply luminol to the cottage floor, hoping to find traces that link the three suspects to the crime. A herd of investigators and six young people, sans booties, have thumped through these rooms since Meredith’s murder.

Top cop Edgardo Giobbi: He fibbed to the Daily Mail, claiming Amanda had left a bloody shoeprint in her own bedroom.

*January 11, 2008. Police leak the fallacious “CSI technique leads Italian police to bloody footprint in Foxy Knoxy’s bedroom” story to the notorious Daily Mail. It claims this incriminating evidence was revealed by luminol “a blood-revealing substance made famous by hit series CSI Miami.” In fact, luminol reacts to many substances. Scientists must do a TMB test to confirm blood. Coincidentally, this leak comes “just hours after police revealed that they had discovered traces of DNA from suspect Raffaele Sollecito on Meredith’s bra” (actually bra clasp). Rudy Guede, condemmed in a separate trial, left DNA on the bra, on the victim, on her handbag and elsewhere.

Who leaked these juicy details to Britain’s nastiest tabloid? None other than Edgardo Giobbi, head of Rome’s elite SCO crime-fighting unit. Boasting that his investigations run on sheer psychology, not forensics, he told private investigator Paul Ciolino that he became very suspicious of Amanda and Raffaele after they were spotted eating pizza, days after the crime. In court, he claimed that Knox had swiveled her hips at him, while donning protective booties at the crime scene. “Oopla,” she is supposed to have said. Before Knox even went on trial, his office posted a photo of the U.S. honor student in its rogues gallery of convicted felons, amid Mafiosi responsible for innumerable atrocities.

“This is a crucial discovery and very important,” Giobbi, boss of bosses, said of the non-existent bloody footprint. ”It was discovered during the examination of the apartment and was in Amanda’s bedroom. At this stage we do not know if it was made by a man or a woman.”

Admitting that investigators would “compare it to the three suspects” and nobody else, he added that “there were also traces of blood found between the room and other parts of the apartment.”

Amanda Knox supposedly showered in this bloody bathroom, which is actually painted with the phenolphthalein. It instantly turns pink in the presence of blood, but after a few minutes, oxidizes and turns pink everywhere, producing the effect seen here. In fact, the room had only minor blood stains that Knox took for menstural blood, since she lived in a flat full of women.

January 16, 2008. Police leak a bloody photograph to the Daily Mail and other tabloids, claiming Amanda showered in a bathroom after the crime that looked like a butcher shop. In fact, the forensics team had treated the room with phenolphthalein, which instantly turns pink when it detects blood and then oxidizes everywhere (see photo at right). The first officers who arrived saw only a few drops on the tap, a slight smear in the bidet and a smudge on a bath mat. They were so unalarmed that they were reluctant to break down the victim’s locked bedroom door to see if she was inside.

October 9, 2008. During Amanda and Raffaele’s pretrial, Dr. Patrizia Stefanoni concedes on the stand that she tested the “bloody” footprints for blood and the TMB test came up negative. But she makes the Orwellian argument, from which she will never retreat, that the court can “presume” the prints were bloody, because the sample was scanty and Rudy’s bloody shoeprints yielded abundant samples. There was, in other words, plenty of the victim’s blood at the crime scene. Guess who Judge Paolo Micheli chooses to be the “independent expert” called in to verify Stefanoni’s results? Her boss, Dr. Renato Biondi. He says everything’s fine. Prosecutor Giuliano Miginini boasts of “unassailable evidence.”

June 12, 2008. Dr. Stefanoni finally releases her report, “Relazione Tecnica Indagine di Genetica Forense” to the defense. It makes the unusual claim that “a scientific assessment of the possible presence of blood can be determined in the presence of samples positive for luminol but negative for tetramethylbenzidine (the blood test).” She still claims the samples were scanty, but the paperwork shows that they were abundant enough for two blood tests, both negative.

*May 15, 2009. Print expert Lorenzo Rinaldi, from Rome’s scientific police, testifies that two luminol-revealed footprints were “compatible” in size with Amanda’s footprints–one leaving her room and another in the hall outside Kercher’s door. Conceding that he’s not a forensics biologist and can’t identify blood traces, he admits under cross-examination that he didn’t compare the prints to the feet of Amanda’s two Italian roommates. Nor can he explain why her footprints would be sinister in her own home. He confirms that luminol reacts to substances other than blood, even fruit juice or rust. Nevertheless reporters, far from America’s tech corridors, gush about his “precise” Powerpoint presentations (which U.S. grade schoolchildren have long ago mastered). Missed in the gushing is the fact that Rinaldi uses “precise” Powerpoints to pin smudgy, unmeasurable footprints to Amanda and Raffaele. Nevertheless, jurors and judges are impressed, right along with the reporters.

May 22, 26, 2009. Police forensics expert Dr. Patrizia Stefanoni talks up the luminol prints, speaking of “presumptive blood,” the same argument she’s been making since pretrial.

July 6, 2009. Amanda’s scientific expert, coroner Sarah Gino, testifies about the luminol-revealed footprints and finds them meaningless, since soil, cleaning products and other substances can react with luminol. Indeed, the prints can’t even be dated and could have been placed there before the murder for innocent reasons. Dr Carlo Torre, speaking for the defense, shows scorn for the luminol footprints, complaining of their vague outlines, the difficulty of measuring them. He wonders aloud why police didn’t take prints from the other roommates.

July 18, 2009.Defense expert Adriano Tagliabracci is on the stand, when prosecutor Manuela Comodi makes a major faux pas. He argues that the DNA on the bra clasp is too scanty to yield reliable results. Dr. Stefanoni feeds information to prosecutor Comodi, who lets it slip that 1.4 nanograms of DNA were found on the bra clasp, The defense complains loudly, wondering why this figure doesn’t appear on any documents. Judge Giancarlo Massei orders Stefanoni to provide all manner of paperwork and closes down court until the fall. This action will finally quantity the amount of DNA on the bra strap and make clear that all of the luminol footprints tested negative for blood.

September 26, 2009. Nope, the luminol prints weren’t bloody, Dr. Sarah Gino reveals. She’s quoted in Judge Giancarlo Massei’s report, released after the verdict: “We learn, contrary to what was presented in the technical report filed by the forensics police, and also to what was said in court, that not only was the luminol test performed on these traces, but also the genetic diagnosis for the presence of blood, using tetramethylbenzidine, and that this test gave a negative result on all evidentiary items from which it was possible to obtain a genetic profile.” As for samples being scanty, Dr. Gino reveals that the famous “Foxy Knoxy” footprint in Amanda’s room shows 240 pg, a significant amount. Not only was it found negative for blood, but also for the victim’s profile. In other words, the luminol footprints had nothing to do with the crime.

November 20, 2009. Prosecutor Comodi defends Dr. Stefanoni’s work during closing arguments, asking jurors to use common sense. She insists that Raffaele made a bloody footprint found on a blue bathmat because he also made (nonexistent) luminol-revealed bloody footprints. Indeed, commonsense would lead one to conclude that Rudy Guede left the bloody footprint, since his bloody shoeprints extend from the victim’s bedroom all the way to the front door.

“At the scene of the crime there is a footprint made in blood on the bathmat and Knox and Sollecito’s footprints made in blood on the floor and these were supposedly made at some different time because they stepped in bleach or rust or fruit juice?” Comodi nevertheless tells jurors. “You decide.”

December 4, 2009. Judges and jurors condem Raffaele and Amanda. When Judge Massei releases his report, he’ll concede that Sarah Gino was right; yes, the prints tested negative for blood. But he uses those undated bloodless footprints, which any of the four roommates could’ve made, to nail Amanda to the crime. Indeed, he has her murdering Meredith in bare feet and then carelessly sauntering around the cottage (while paradoxically performing a magical cleanup, removing all trace of her and Raffaele from the murder room, without disturbing Rudy’s traces). Actually, forensics investigators who never changed their booties did walk through this crime scene and all around the cottage, but no mention is made of them. Instead, Judge Massei returns to Dr. Stefanoni’s “presumptive blood theory.”

Note the word “appear” in bold below, because that’s where he starts penning a crime novel, and not for the first time in this report. I’ve marked the most fallacious, prejudicial parts in boldface. Recall that Judge Massei has no scientific degree and refused to let independent experts look at the DNA tests in the Knox case. Now, post-trial, he introduces a footprint analysis method never vetted by any forensic biologist on the planet. Recall that he deliberated with the jurors and was looked to as the “expert” in the case. They never debated Amanda and Raffaele’s guilt or innocence, only whether they should get life (30 years) or a lesser sentence. They felt they were being kind when they gave Amanda 26 years; Raffaele, 25. The two college students are appealing their convictions. Rudy Guede, to whom nearly all evidence points, got 30 years at trial and 16 upon appeal.

Judge Massei imagines Amanda tiptoeing around in bloody feet after stabbing poor Meredith to death, neatly accounting for all of the luminol-enhanced footprints. In reading this, I wonder, when is the burden of proof ever placed on the prosecution in Italy? This is backward:

“The luminol-revealed prints, whose presence in several places in various rooms of the cottage was explained by reference to fruit juice, bleach, various vegetables, rust, and so on, but appear, on the contrary, to be explainable if one holds that the Luminol gave off fluorescence because of the presence of blood. In this regard, one cannot simply disregard the fact that the bloodstains were undeniably abundant in Meredith’s room, from which easily, or indeed inevitably, they must have been exported to other parts of the house by anyone who, coming out of Meredith’s room, went into these other parts. This is seen for the shoes of Rudy Guede, marking their owner’s footsteps along the corridor towards the exit from the house; it was seen for the traces found in the bathroom; it should be considered that also happened for the traces found in Romanelli’s room, in Knox’s room, in the corridor, and it should be pointed out that two of these traces give a mixed biological profile of Amanda and Meredith, and the others the biological profile of Amanda alone. She, it must therefore be held, washed Meredith’s blood off her bare feet, but on the soles some bloody residue must have remained, and when she went into her own room, into Romanelli’s room and passed through the corridor, and in several points in the room[s] where she had passed, she left the traces that were discovered.”

April 19, 2010. Amanda and Raffaele appeals documents filed. They note that Dr. Stefanoni continues to argue presumptive blood because the sample was scanty, even though her own testimony disproves that. “From the reading of the statements of the geneticist on October 4, 2008, in fact, it shows that–before the DNA extraction–the same had provided and carried out at least two tests–about the blood nature of the trace: generic tetramethylbenzidene (TMB) test for the presence of blood. The TMB test is specific for blood. Both tests gave a negative result.

March 2011. Wikipedia finally deletes “made in blood” from its prejudicial list of evidence: “Luminol revealed footprints made in blood in the flat, compatible with the feet of Knox and Sollecito.” It continues to hint that a bloody shoeprint left by a woman was found on the pillowcase under the victim–although no science supports this police contention. Indeed, only traces of Rudy Guede were found in the murder room, and those traces were everywhere.

MURDER IN ITALY, my book on the spell-binding Amanda Knox case, is a Library Journal Bestseller. Winner of Best True Crime 2010 Editor’s Choice and Reader’s Choice awards. Called “a real-life murder mystery as terrifying and compelling as fiction,” it’s built on diary excerpts, wiretaps, court scenes, trial transcripts, first-hand experience and interviews with key players for all sides.

MURDER IN ITALY is online at Amazon.com, Barnes & Noble, Indiebound and bookstores. It’s also a Kindle & ebook. I’ll blog about the Knox case until the final appeal.